Tribulus terrestris has a long history of use for a variety of conditions. It has been suggested that it was used in ancient Greece and India as a physical rejuvenation tonic. In China, it is used as a component of therapy for conditions affecting the liver, kidney, cardiovascular system and immune systems. It has also been used in Eastern European folk medicine for increased muscle strength and sexual potency. Despite its history of use, there is limited human data available in order to evaluate its clinical effectiveness.

Tribulus has been studied as a non-steroidal alternative to treatment of infertility. Although the results of the few studies done with the combination product Tribestan® are promising, more studies are needed in order to further evaluate its clinical effectiveness. Preliminary research with tribulus also suggests that it may be useful in treating coronary heart disease, but additional study is needed.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Preliminary research suggests that tribulus may be beneficial to patients with coronary heart disease. Additional study is needed to further evaluate its clinical effectiveness.

C

Preliminary studies indicated that tribulus may enhance body composition or exercise performance in resistance trained males. More information is needed before a firm recommendation can be made.

C

Although the results of one study investigating the effects of Tribulus terrestris are encouraging, larger studies of better design are needed in order to evaluate the effectiveness of Tribestan® in treatment of female infertility.

C

Although Tribestan® seems to increase sperm count and viability and increase libido, its effectiveness in the treatment of male infertility remains inconclusive, due to a lack of well-designed clinical trials.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

There is no proven safe or effective dose for tribulus; 85-250 milligrams of 40% furostanol saponins extract in three divided doses with meals has been used. For exercise performance enhancement, 3.21 milligrams per kilogram of tribulus for eight weeks has been used.

Children (younger than 18 years):

There is no proven safe or effective dose for tribulus in children.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in individuals with a known allergy or hypersensitivity to Tribulus terrestris or its constituents.

Side Effects and Warnings

Tribulus terrestris appears to be generally safe with a few adverse events of insomnia and menorrhagia (heavy menstrual bleeding) occurring. Use cautiously in patients with menstrual disorders. One case of pneumothorax (air between the lungs and the lining of the chest cavity) upon digestion of the fruit has been reported. In another case report, the patient developed a polyp in the lobar bronchus of the right interior lobe due to the presence a tribulus fruit spine. In a case report, gynecomastia (excessive development of male breasts) was observed in a weight-trainer taking an herbal supplement containing tribulus.

Most adverse effects reported, such as exceptionally strong libido, general excitation, and insomnia have been from use of the combination product Tribestan®. However, these adverse effects cannot be solely attributed to tribulus, due to the other ingredients in this product.

Although not well studied in humans, a saponin from tribulus may reduce levels of glucose and total cholesterol. Use cautiously in patients with diabetes (high blood sugar) or using hypoglycemic (blood sugar altering) medication, as tribulus may decrease blood sugar levels.

Although not well studied in humans, tribulus may increase prostate weight. Use cautiously in patients with benign prostatic hyperplasia (enlarged prostate) or prostate cancer.

Pregnancy and Breastfeeding

Tribulus is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence. Traditionally, tribulus has been used as an abortifacient (induces abortion).

Tribulus may add to calcium channel blocker or beta-blocker effects due to its negative chronotropic activity in cardiac muscle.

Tribulus may exacerbate digoxin effects. Caution is advised.

Tribulus may exhibit diuretic effects (increases urine flow). Caution is advised when used with other drugs that have diuretic effects.

Tribulus may lower blood glucose levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Tribulus has been found to have blood pressure lowering effects, and may affect patients taking drugs that also alter blood pressure.

Based on preliminary study and studies of combination products containing tribulus, tribulus may increase levels of steroid hormones.

Interactions with Herbs and Dietary Supplements

Tribulus may exacerbate the effects of cardiac glycoside herbs.

Tribulus may exhibit diuretic effects (increase urine flow). Caution is advised when used with other herbs that have diuretic effects.

Tribulus may lower blood glucose levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Tribulus has been found to have blood pressure lowering effects, and may affect patients taking herbs that also alter blood pressure.

Based on preliminary study and studies of combination products containing tribulus, tribulus may increase levels of steroid hormones.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.